Manual (e.g., trial and error) paper folding techniques have been studied for hundreds of years. Recently, such techniques have been applied to the creation of greeting cards that unfold into complex shapes as the card is opened. FIG. 1 illustrates an example of such "pop-up" greeting cards. As shown, pop-up cards have an underlying base card 100 to which is attached several pieces 102 that move as the card halves 104, 106 are actuated (e.g., opened and closed) along a fold line 108. Although card pieces generally operate by being placed in combination with the fold line 108, FIG. 1 shows that remote (from the fold line) card pieces can be actuated through use of a tab 110 that can be affixed across the fold line to transfer the effect of actuating the card halves.
A problem with creating designs such as FIG. 1, however, is that determining proper placement of the card pieces 102, 110 is largely a trial and error procedure. That is, a designer generally conceives of a design, cuts out pieces, folds and glues them, waits, and then tests the resulting construction. If it doesn't look quite right, or operate correctly, the designer's only recourse is to re-cut the pieces with slightly different shapes, fold, glue, wait, and try out this second construction. Once again, if the pieces are not formed or placed correctly, the cutting and placement steps must be repeated until the design is eventually achieved (or the designer gives up). What is needed is a way to design and test a card before trying to construct it.